just add up the costs:
50x + 40(x-3) = 600
50x + 40x - 120 = 600
90x = 720
x = 8
A girl buys x magazines at 50p each and x-3 magazines at 40p each. She spends £6 in all. Find x?
2 answers
0.5x + 0.4(x-3) = 6
0.5x + 0.4x - 1.2 = 6
0.9x = 7.2
x = 8
0.5x + 0.4x - 1.2 = 6
0.9x = 7.2
x = 8
2 answers